Electrode for measuring electrophysiological signals using liquid electrolytic gel with a high salt concentration

Abstract

An electrophysiological electrode includes multiple layers of materials to isolate liquid electrolytic gels from the conductive inks on the flexible circuit of the electrode substrate. Such an electrode has a much longer shelf life under normal storage conditions than other electrodes of such construction with high salt content liquid electrolytic gel, and is able to maintain acceptable impedance upon its eventual use.

What is claimed is:  
     
       1. An electrode for measuring electrophysiological signals, the electrode comprising: 
       a substrate of flexible non-conductive non-metallic material;  
       a conductive metal ink layer deposited on said substrate;  
       a physically distinct barrier layer of silver/silver chloride (AG/AgCl) deposited over and contiguous with said conductive metal ink layer,  
       predispensed salt content based conductive gel;  
       wherein said barrier layer isolates said conductive ink layer from said conductive gel.  
     
     
       2. The electrode of  claim 1  wherein said barrier layer comprises a component plated with Ag/AgCl material. 
     
     
       3. The electrode of  claim 1  wherein said barrier layer comprises a screen printed ink layer of Ag/AgCl material. 
     
     
       4. The electrode of  claim 1  wherein said barrier layer comprises a flexo-printed ink layer of Ag/AgCl material. 
     
     
       5. The electrode of  claim 1  wherein said conductive metal ink layer is silver (Ag). 
     
     
       6. The electrode of  claim 1  wherein said conductive gel is a liquid electrolytic gel. 
     
     
       7. The electrode of  claim 1  wherein said conductive gel is a solid hydrogel gel. 
     
     
       8. The electrode of  claim 1  wherein printed graphics are printed on a side of said flexible substrate opposite the side where said conductive metal ink layer is located. 
     
     
       9. An electrode for measuring electrophysiological signals, the electrode comprising: 
       a conductive gel;  
       a substrate of flexible non-conductive material;  
       a conductive ink circuit printed on said substrate;  
       a barrier layer of conductive material placed between said conductive ink circuit and said gel;  
       a ring or pad of nonconductive material positioned between a surface of said flexible substrate bearing a conductive ink circuit and said barrier layer of conductive material, said ring or pad of nonconductive material extending from the outer edge of the barrier layer of conductive material to an extent sufficient to act as an isolating gasket to completely separate the conductive ink circuit from the conductive gel.  
     
     
       10. An electrode for measuring electrophysiological signals, the electrode comprising: 
       a conductive gel;  
       a substrate of flexible non-conductive material;  
       a conductive ink circuit printed on said substrate;  
       a barrier layer of conductive material placed between said conductive ink circuit and said gel, said barrier layer being a solid hydrogel.  
     
     
       11. The electrode of  claim 9  wherein said nonconductive material is a transfer film. 
     
     
       12. The electrode of  claim 9  wherein said nonconductive material is a double coated adhesive foam backing. 
     
     
       13. The electrode of  claim 9  wherein said barrier layer of conductive material is secured to said ring or pad of nonconductive material and to said flexible substrate bearing a conductive ink circuit by means of a snap or ring that is pressure fit to such barrier layer. 
     
     
       14. The electrode of  claim 9  wherein said conductive ink circuit is made of carbon ink. 
     
     
       15. The electrode of  claim 9  wherein said barrier layer of conductive material is a layer of Ag/AgCl.